var obj = {
  name: "frank",
  age: 18,
};

Object.defineProperty(obj, "address", {
  // enumerable: true,
  value: "北京市",
});

// console.log(obj);

function Person() {}
var p1 = new Person();
console.log(Person.prototype.constructor);
console.log(Object.getPrototypeOf(p1).constructor);
